Summary

The toLocaleString() method returns a string with a language sensitive representation of this date. The new locales and options arguments let applications specify the language whose formatting conventions should be used and customize the behavior of the function. In older implementations, which ignore the locales and options arguments, the locale used and the form of the string returned are entirely implementation dependent.

The locale matching algorithm to use. Possible values are "lookup" and "best fit"; the default is "best fit". For information about this option, see the Intl page.

timeZone

The time zone to use. The only value implementations must recognize is "UTC"; the default is the runtime's default time zone. Implementations may also recognize the time zone names of the IANA time zone database, such as "Asia/Shanghai", "Asia/Kolkata", "America/New_York".

hour12

Whether to use 12-hour time (as opposed to 24-hour time). Possible values are true and false; the default is locale dependent.

formatMatcher

The format matching algorithm to use. Possible values are "basic" and "best fit"; the default is "best fit". See the following paragraphs for information about the use of this property.

The following properties describe the date-time components to use in formatted output, and their desired representations. Implementations are required to support at least the following subsets:

weekday, year, month, day, hour, minute, second

weekday, year, month, day

year, month, day

year, month

month, day

hour, minute, second

hour, minute

Implementations may support other subsets, and requests will be negotiated against all available subset-representation combinations to find the best match. Two algorithms are available for this negotiation and selected by the formatMatcher property: A fully specified "basic" algorithm and an implementation dependent "best fit" algorithm.

weekday

The representation of the weekday. Possible values are "narrow", "short", "long".

era

The representation of the era. Possible values are "narrow", "short", "long".

year

The representation of the year. Possible values are "numeric", "2-digit".

month

The representation of the month. Possible values are "numeric", "2-digit", "narrow", "short", "long".

day

The representation of the day. Possible values are "numeric", "2-digit".

hour

The representation of the hour. Possible values are "numeric", "2-digit".

minute

The representation of the minute. Possible values are "numeric", "2-digit".

second

The representation of the second. Possible values are "numeric", "2-digit".

timeZoneName

The representation of the time zone name. Possible values are "short", "long".

The default value for each date-time component property is undefined, but if the weekday, year, month, day, hour, minute, second properties are all undefined, then year, month, day, hour, minute, and second are assumed to be "numeric".

Examples

Example: Using toLocaleString

In basic use without specifying a locale, a formatted string in the default locale and with default options is returned.

var date = new Date(Date.UTC(2012, 11, 12, 3, 0, 0));
// toLocaleString without arguments depends on the implementation,
// the default locale, and the default time zone
date.toLocaleString();
// → "12/11/2012, 7:00:00 PM" if run in en-US locale with time zone America/Los_Angeles

Example: Checking for support for locales and options arguments

The locales and options arguments are not supported in all browsers yet. To check whether an implementation supports them already, you can use the requirement that illegal language tags are rejected with a RangeError exception:

Example: Using locales

This example shows some of the variations in localized date and time formats. In order to get the format of the language used in the user interface of your application, make sure to specify that language (and possibly some fallback languages) using the locales argument:

var date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));
// formats below assume the local time zone of the locale;
// America/Los_Angeles for the US
// US English uses month-day-year order
alert(date.toLocaleString("en-US"));
// → "12/19/2012, 7:00:00 PM"
// British English uses day-month-year order
alert(date.toLocaleString("en-GB"));
// → "20/12/2012 03:00:00"
// Korean uses year-month-day order
alert(date.toLocaleString("ko-KR"));
// → "2012. 12. 20. 오후 12:00:00"
// Arabic in most Arabic speaking countries uses real Arabic digits
alert(date.toLocaleString("ar-EG"));
// → "٢٠‏/١٢‏/٢٠١٢ ٥:٠٠:٠٠ ص"
// for Japanese, applications may want to use the Japanese calendar,
// where 2012 was the year 24 of the Heisei era
alert(date.toLocaleString("ja-JP-u-ca-japanese"));
// → "24/12/20 12:00:00"
// when requesting a language that may not be supported, such as
// Balinese, include a fallback language, in this case Indonesian
alert(date.toLocaleString(["ban", "id"]));
// → "20/12/2012 11.00.00"

Example: Using options

The results provided by toLocaleString can be customized using the options argument: